1. Field of the Invention
The present invention relates to a vibratory grain sorting machine.
2. Description of the Prior Art
A generally known vibratory grain sorting machine comprises a frame having fixedly mounted thereon a stack of sorting plate members. An assembly to be vibrated including at least the frame and the stack o sorting plate members fixedly mounted thereon is inclined with respect to the horizontal plane so that a bottom wall of the frame has an upper edge and a lower edge. The assembly to be vibrated is supported on a base structure by four strut units. A first pair of strut units are spaced from each other along the lower edge of the bottom wall of the frame and have respective top ends pivotally connected to the bottom wall of the frame adjacent to the lower edge thereof and respective bottom ends pivotally connected to the base structure. A second pair of strut units ar spaced from each other along the upper edge of the bottom wall of the frame and have respective top ends pivotally connected to the bottom wall of the frame adjacent to the upper edge thereof and respective bottom ends pivotally connected to the base structure.
The thus constructed vibratory grain sorting machine is disclosed in Japanese Patent Laid-Open Nos. 56-144781 and 56-144782 filed in the name of Toshihiko Satake who is the same as the inventor of the present application and laid open to public inspection on Nov. 11, 1981. The disclosure in these Satake patent applications is incorporated as a reference into the present specification. In addition, reference should be made to Japanese Patent Laid-Open No. 51-114251 filed in the name of Toshihiko Satake who is the same inventor as the present inventor, and laid open to public inspection on Oct. 7, 1976 and Japanese Patent Publication No. 55-11391 filed in the nam of Toshihiko Satake who is the same inventor as the present inventor, and published for opposition purpose on Mar. 25, 1980. The sorting machine disclosed in the above-described Japanese Patent Laid-Open No. 51-114251 includes a frame having a bottom wall disposed horizontally.
In the conventional sorting machine comprising a frame having an upper edge and a lower edge and first and second pairs of strut units each of which has the top end pivotally connected to the bottom wall of the frame, the minimum height of the assembly to be vibrated, with respect to the base structure is determined by the longitudinal dimension of the first pair of strut units. This would inveitably result in the increase in height of the assembly to be vibrated, with respect to the base structure and would result in the reduction in stability of the overall sorting machine.
In addition, it is not known to connect the vibrating device of the conventional sorting machine to the frame so as to apply a vibratory force to the assembly to be vibrated, toward and away from the gravitational center of such assembly. Consequently, there results a rotational moment around the gravitational center of the assembly to be vibrated. Such rotational moment causes an impact force to be applied to the respective pivotal connections between the frame and the top ends of the strut units and the respective pivotal connections between the base structure and the bottom ends of the strut units, resulting in the reduction in durability of these pivotal connections.
Moreover, the vibrating device of the conventional sorting machine is mounted on the base structure at a location below the frame. This makes it difficult for an operator to have accessibility to the vibrating device for the purpose of maintenance and inspection.